Mercury blackmax 150

[MuskyHunterMichael]

I have a mercury blackmax 150 it runs at home with earmuffs on but when I take it to the lake it does not want to run. It only has 1000 rpm at full throttle. I have replaced the fuel lines and put a new primer ball in. I put a online filter between the tank and the primer ball. I had the carbs rebuilt and cleaned last year. I am at a loss on what it could be any help would be appreciated

 

[jimmbo]

Compression, Spark at the proper Time, and Fuel, combined are what makes a Motor run.
Start with a Compression Test
Does it have Spark good enough to jump a 3/8" gap on every Plug Wire?
Fuel... Is fuel getting to all carbs? Are all the carbs synced to each other as well as being synced to the Spark Advance?

 

[MuskyHunterMichael]

I’m unsure on how to check if the carbs are synced

 

[jimmbo]

The linkages that connect the Throttle shafts on each carb to the other, have to be adjusted so are all closed at the same time. The Sync between the Spark and Throttle Linkage is bit more complicated, and a Factory Service Manual is your best bet there. Any time the Carbs are removed, both sync have to be checked and adjusted if need be

 

[Chris1956]

I would recommend a factory service manual. The timing is critical and is the synch between carbs and ign timing. The service manual will guide you thru it. This motor is not the same as a lawnmower or chainsaw.

 

[ThomW]

If you had the carbs rebuilt last year, it would be essential that they were linked and synced. Also need to make sure timing advance and other things are set correctly. What year is your motor? I may have a pdf version of the manual you can look at.

 

[MuskyHunterMichael]

If you had the carbs rebuilt last year, it would be essential that they were linked and synced. Also need to make sure timing advance and other things are set correctly. What year is your motor? I may have a pdf version of the manual you can look at.

It is a 1982

 

[ThomW]

Alright. The manual I have is for 1992 and newer...so probably won't be exactly what you are needing. I'm happy to share it to give you an idea of what the syncing of the carbs entails, but you will want to find a manual for your motor and check the above mentioned things.

 

[Chris1956]

The link and synch from a '92 probably works for him. Not much changed in that era, as far as link and synch. The throttle arm may be a bit different..

 

[Dukedog]

It is a 1982

 

[MuskyHunterMichael]

I messaged you

 

[Dukedog]

I messaged you

tried to attach to your email.. says file is to big.. gives me some kinda geek instructions on what ta do.. will need ta get one of my kids ta explain what needs ta be done to send.. sorry..

 

[QBhoy]

Hi. Most will know by now…I love a simple and easy solution attempt.
I’d start with checking that the primer bulb and fuel filter you fitted are going the correct direction. Very common and easy to get them the wrong way. Most are uni directional. Have a wee look…before you start tearing things to bits